Toll switchboard



Jan. 18, 1944. 1.. F. PORTER 2,339,425

TOLL SWITCHBOARD Filed June 27, 1942 2 Sheets-Sheet 2 DISCONNECT INVENTOR ATTORNEY L. F PORTER I Patented Jan. 18, 1944' Tort "swIToHBoARD lseslieficlorterfHoboken, N. J., assignor to Bell Telephone "Laboratories, Incorporated, New York, N.- Y., a corporation of New York application 211M627, 1942, Serial No. 448,721

This invention relates to toll switching systems and more particularly to a method of, and circuit arrangement for, handling a large volume of calls at existing outward toll switchboards by enabling full use to be made of all-of the cord circuits at certain or all of the regular operators positions which method and arrangement are objects of the invention.

At outwardtoll positions the principal work of the operator consists in answering calls from subscribers, determining the connection wanted, writing up the ticket, "plugging int-o a trunk to the location desired, ringing when necessary, and repeating the numberto the distant operator. The toll operator then times the call and disconjnejcts its termination. Each toll operator usually has from six to eightcords, but the position is generally arranged to accommodateten cords but the number of cords provided depend on the type of calls most commonly handled at the position,

i e., on the average amount of time required to handle each call. Trafiic surveys have shown,

however, t hat where toll positions are equipped with six cords, only two cords, on the average arej'in u'se at any 'onetimeand that where eight cordsare provided, the average number in use at onetime is two and one-half cords The comparatively large number of; spare cords are provided to insure that under no condition will ah"oprator'be unable'to coiii zrlete calls because "cords are not available.

"A feature of the present inventioniwhereby the foregoing object is attained, resides in the provision of a so oalled' supplementary or cabinet ope ators position for eveif'ytwo or three pairs of cords at predetermined"switchboard positions through which supplementary positions the respectivetwo or three cord pairs can be connected or looped, at the will of th'switchb'oard operator, by means of amanually'controlled switching operation.

These cabinets or supplementary positions are so constructed and arranged that'when the cords of a switchboard'po'sition areftransferred thereto the insertion of ana'nswering plug of a cord pair in a calling line jack causes an operator atIthe respective supplementary position to be automatically signaled whereupon she can answer and talk to the calling subscriber to ob'tain'and record the details 'of the call. Thereafterthesupplecalling end of the respectivec'ord pair to the deor the cord, talk over both the calling and called ends simultaneously, or in' either'direction to the exclusion of the other, time the call, receive supervisory signals from both' the calling and called lines, and at the conclusion of the conversation signal the'switc'hbo'ard operator toremove the cord circuit plugs thus discontinuing theflconnection.

During the time the cords of a switchboard position are connected through supplementary ing operator, 1. e., sheplugs up calling linesjputs up connections to called lines and disconnects at sired outgoing line, following whichthe"supplev "m'entary operator can ring out over eith'r' and the direction of the supplementaryoperator, but otherwise does'not involve herself in the progress of the calls other than to perform suchjs'pecial function as dialing, key pulsing, coincontrol, and number checking, when requested to 'do so by the supplementary operators.

By means of this arrangement an existing regulartoll position equipped'with from six to ten pairs 'of cords can be, employed'to its full cord capacity with the assistance of from threeto 'five supplementary cabinet operators, it"being understood as before mentioned, that 'a'single't'oll operator is normally unable to establish and supervise an average of a little more than two'outwarcl 'lowing'description when read in connection with the'accompanying drawings, Fig. 1 of which represents a single one of a plurality of toll switchboard cord pairs arranged to be connected by means of a transfer'key common to all of'the cords at the position, to a so-called supplementary o perators position shown in Fig. 2.

The cord circuit 'shOwnfat the top ofFig. 'l,

is similar to the cord circuit shown in Fig. 1

of U, S. Patent 2,276,515, iss'ued'March 17, I942,

' to T. D. Robb, modified to the extentthat certain of the conductors in 'the'front or calling end of the cord are connected toa transfer relay l con trolled by a key TR, shownin the lower righthand corner of the'drawing whereby, when the key isoperated, these conductors will be extended to the "supplementary'position circuit'SPshown "in' Fig.2.

Let be"a'ssurn'ed that atoll ofiei'atof'spo'sitron represented by" toll' cord TC "which "position is modified and arranged for emergency or supplementary operators assistance in accordance with the invention, becomes overloaded to the extent that the number of calls awaiting attention greatly exceed the ability of the toll operator to perform the necessary acts required to give prompt and satisfactory service. When this condition is recognized, or anticipated in advance, as many auxiliary operators as appear to be required in the emergency will be assigned by a supervisor, to so-called cabinet positions SP, represented by Fig. 2 of the drawings, which cabinet positions are located wherever convenient and connected by wires to transfer relay I located at the toll switchboard.

The toll operator or supervisor may then operate the positional transfer key TR thereby operating relays, such as I, individual to each cord at the position which extend certain of the respective cord conductors to the supplementary positions. In practice, two supplementary operators positions will be located at a single cabinet or desk to which cabinet five switchboard cords will usually be extended by the operation of TR, and the consequent operation of the five individual relays corresponding to relay I.

For simplicity we will, hereinafter, confine our consideration of the invention to a single toll cord TC and assume that an overload on the respective toll position is imminent, or has occurred, and further that the corresponding supplementary or assistant operator's position is occupied and relay I is operated thus connecting the cord TC to the supplementary position SP.

As we have assumed that an operator is in at tendance at the supplementary position to which the cord TC is now connected, as soon as the supplementary operator is free to handle a call she will operate the awaiting call key 2 and the talk key 3. Ke 2 operated connects ground over its contacts 4, contacts 5 of key 3, now operated, conductor 6, and contacts I of relay I to battery through the front cord supervisory lamp 8 which lights as an indication to the toll operator that a supplementary operator is ready to handle the next incoming call.

Operation of key 3 connects, at its contacts 9 and ID, the operators telephone circuit OT to the tip and ring of the cord TC in an obvious circuit which includes contacts of the sleeve keys II and I2, ringing keys I3 and I4 and transfer relay I.

Now, when the next call is received over an incoming trunk jack I09, the toll operator will insert the answering plug I08 of'cord TC into that jack whereupon the supplementary operator, whose telephone set is connected to the cord, will distinguish the usual characteristic hum or line noise in her receiver as a signal that a calling line has been plugged up whereupon she will restore the awaiting-call key 3 thereby extinguishing supervisory lamp 8 and talk to the calling subscriber to secure the details of the desired connection which she will record in the usual manner.

. After securing the necessary information on the call the supplementary operator will then operate key I8 thereby causing the front cord supervisory lamp 8 to flash undercontrol of interrupter I in a circuit which can be traced from ground, intermittently closed contact of interrupter relay I9, contacts of key I3, contacts 2I of key 2, now released; contacts 5 of key 3, conductor 6, and contacts I of relay I to battery in series with lamp 8. Noting the flashing of lamp 8 the toll operator will actuate her talk key I00 thereby causing her telephone set, not shown, to be connected to the cord as shown in the Robb patent referred to thus placing the supplementary operator and toll operator in communication.

The operation of key I8, while the talking key 3 is operated, connects ground at contact 22 of key 3 over contacts 23 of key I8, conductor 24, contacts 25 of relay I, to the sleeve conductor 26 of the front toll cord to maintain the tip and ring conductors continuous from end to end during the time the toll operators talk key is operated as shown in the aforementioned Robb patent.

After the supplementary or cabinet operator has given the toll operator the necessary instructions, she will restore keys I8 and 3. Key I8, restored, opens its contacts 20 to extinguish lamp 8 as an indication that the toll operator can insert the trunk or calling plug I26 in the designated out-trunk jack I29 and release her talk key I00. Release of the toll operator's talk key itu releases the cord relay IUI which operated when the talk key was operated. This relay released, extends the sleeve conductor I26 over contacts 29 of relay I0i, conductor 30, contacts 3i of relay I, conductor 32, and contacts 33 of the released talk key 3 to battery through the fron supervisory lamp 34 of the supplementary position, which lamp 34 lights when the plug I28 is inserted in jack I29, thereby connecting a low resistance ground to the sleeve conductor 25. This indicates to the supplementary operator that the calling end of the cord circuit has been connected to the desired trunk.

The supplementary operator may now ring on this connection by operating her front cord ringing key It thereby connecting ringing current from source to the front plug I26 to the exclusion of the answering end of the cord. When the distant end of the outgoing called trunk is seized the resistance to ground on the sleeve of jack I29 is changed to a sufllciently high value to darken lamp 34.

Operation of either of the splitting keys II or I2, in conjunction with operation of the talk key 3, permits the supplementary operator to talk over either end of the cord to the exclusion of the other end.

The operation of monitoring key 36 connects ground to operatemonitoring relay 31 which connects the operators receiver to the tip and ring of the cord to the exclusion of the operators transmitter.

Reoperation of talk key 3 and key I8 causes the front supervisory lamp 8 to flash, in the same manner as previously described, as a recall signal to the toll operator who answers by operating her talk key I60 whereupon the two operators can talk together.

When the distant called end of the connection is disconnected, supervisory lamp 34, at the supplementary position, relights and when th calling trunk is disconnected at its originating end the sleeve resistance to ground of jack I09 is lowered sufliciently to permit the rear super- ;isgry lamp 38 in the supplementary position to When the supplementary operator observes both lamps 34 and 38 lighted she may signal the toll operator to disconnect by operating the disconnect key 39 thereby connecting ground to the rear supervisory lamp I II of the cord to cause it to light as a disconnect signal.

When the toll operator removes both plugs I08 andl26' from their respective jacks, supervisory lamps 34 and 38 will be extinguished and the supplementary operator will immediately operate her talk key 3 and the awaiting call key 2 thereby placing herself in readiness for the next call.

What is claimed is:

1. In a telephone system, lines, a main operators position, a cord circuit thereat for interconnecting said lines, an auxiliary operators position, means for serially looping said cord circuit, intermediate the two ends thereof, through said auxiliary position, and means at said auxiliary position for enabling the performance thereat of certain of the routine operating functions normally performed at the main operators position.

2. In a telephone system, calling and called lines, a main operators position, a plurality of cord circuits thereat having answering and calling ends, a plurality of auxiliary operators positions fewer in number than said cords, manually controlled switching means adapted when operated to serially connect individual ones of said auxiliary positions intermediate the ends of two or more of said cords, and switching and signaling means at said auxiliary positions for enabling the performance thereat of certain 01 the operations incident to the establishment and supervision of a conversational connection by an associated cord circuit which operations are normally performed at the main operators position.

3. In a telephone system, a calling and a called line, a main operators position, a cord circuit thereat having answering and calling ends for connecting said calling and called lines, an auxiliary operators position, means for serially connecting said auxiliary position intermediate the ends of said cord and means at said auxiliary position for talking, ringing and monitoring on a line connected to either end of said cord independent of the operator at the main position.

4. In a telephone system, calling and called lines, a main operators position, a cord circuit thereat having answering and calling ends for connecting a calling to a called line, a supervisory lamp at each end of the cord, an auxiliary operators position, manually controlled switching means for serially connecting said auxiliary position intermediate the ends of said cord and means controlled at said auxiliary position for lighting either supervisory lamp independent,

of the connection of said cord to a line.

5. In a telephone system, callin and called lines, a main operators position, a cord circuit thereat having answering and calling ends for connecting a calling to a called line, a supervisory lamp at each end of the cord, an auxiliary operators position, manually controlled switching means for serially connecting said auxiliary position intermediate the ends of said cord and means controlled at said auxiliary position for lighting either supervisory lamp independent of the connection of said cord to a line and other means controlled at said auxiliary position for flashing the supervisory lamp associated with the calling end of said cord.

6. In a telephone system, calling and called lines, a main operators position, a cord circuit thereat having answering and calling ends for connecting a calling to a called line, a supervisory lamp associated with each end of the cord. an auxiliary operators position, manually controlled switching means for serially connecting said auxiliary position intermediate the two ends of the cord and means at said auxiliary position for receiving supervisory signals from lines connected by said cord to the exclusion of the supervisory signals from lines connected by said cord to the exclusion of the supervisory lamps associated with the cord.

LESLIE F. PORTER. 

